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131.
Z. Vager H. Feldman D. Kella E. Malkin E. Miklazky J. Zajfman R. Naaman 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,19(4):413-418
New non linear isomers of C n forn=4, 5, 6 have been observed using the combination of the laser photodetachment technique and the Coulomb Explosion Imaging method. Electron affinities of these isomers were found to be lower than the corresponding known linear isomers. The structure of low electron affinity C4 isomer was found to be rhombic in accordance with recent theory. Indications for the non linearity of the low electron affinity isomers of C5 and C6 are also presented. 相似文献
132.
Abstract –An acoustic method is outlined to detect triplet states formed by radical pair recombination in photosyn-thetic reaction centers. It is based on magnetic field effect on the probability of triplet state formation by recombination. Using a periodically modulated magnetic field in the presence of constant exciting light, a periodic modulation of the triplet state concentration is set in the sample, which is detected through the corresponding modulated heat emission, transduced to acoustic vibration of the gas phase around the sample. This effect is similar to the photoacoustic effect, except that here the light is not modulated. The feasibility of detecting such an effect was proven experimentally, by obtaining a signal from quinone-depleted reaction centers of Rhodobacter sphaeroides. The signal had twice the frequency of the magnetic field modulation; it was proportional to the light intensity and significantly stronger at the lower temperatures (in the investigated range 113–278 K). No signal was obtained from quinone-containing reaction centers, which do not produce triplets. A theoretical outline of the effect and the experimental set-up are described. The "magnitude of the effect was calibrated against ordinary photoacoustic measurements, allowing numerical evaluation of certain parameters of the triplet state ( e.g. triplet energy or yield) with the aid of auxiliary information from the literature. 相似文献
133.
G. S. Shakurov V. F. Tarasov B. Z. Malkin A. I. Iskhakova L. A. Kasatkina J. Heber M. Altwein 《Applied magnetic resonance》1998,14(4):415-426
The hyperfine structures of submillimeter EPR spectra of CsCdBr3:Tm3+ and CaF2:Dy2+ single crystals have been resolved and analyzed. The crystal field parameters and the magnetic hyperfine constants are obtained from fitting the envelopes of the simulated spectra to the measured signals. From the specific peculiarities of the hyperfine structure the energy of the interion interaction in the thulium dimers in CsCdBr3 is determined. The isotopic shift of the crystal field splitting in energy patterns of dysprosium isotopes in CainF2 is estimated. 相似文献
134.
We consider the canonical symplectic structure on the moduli space of flatg-connections on a Riemann surface of genusg withn marked points. Forg being a semisimple Lie algebra we obtain an explicit efficient formula for this symplectic form and prove that it may be represented as a sum ofn copies of Kirillov symplectic form on the orbit of dressing transformations in the Poisson-Lie groupG
* andg copies of the symplectic structure on the Heisenberg double of the Poisson-Lie groupG (the pair (G, G
*) corresponds to the Lie algebrag).Supported by Swedish Natural Science Research Council (NFR) under the contract F-FU 06821-304Supported in part by a Soros Foundation Grant awarded by the American Physical Society 相似文献
135.
136.
137.
Plomp M Leighton TJ Wheeler KE Pitesky ME Malkin AJ 《Langmuir : the ACS journal of surfaces and colloids》2005,21(23):10710-10716
Our previous atomic force microscopy (AFM) studies successfully visualized native Bacillus atrophaeus spore coat ultrastructure and surface morphology. We have shown that the outer spore coat surface is formed by a crystalline array of approximately 11 nm thick rodlets, having a periodicity of approximately 8 nm. We present here further AFM ultrastructural investigations of air-dried and fully hydrated spore surface architecture. In the rodlet layer planar and point defects as well as domain boundaries similar to those described for inorganic and macromolecular crystals were identified. For several Bacillus species rodlet structure assembly and architectural variation appear to be a consequence of species-specific nucleation and crystallization mechanisms that regulate the formation of the outer spore coat. We propose a unifying mechanism for nucleation and self-assembly of this crystalline layer on the outer spore coat surface. 相似文献
138.
Benjamin A. Horwitz Shmuel Malkin Jonathan Gressel† 《Photochemistry and photobiology》1984,40(6):763-770
Roseoflavin, an analog known to compete with riboflavin in Lactobacillus casei , riboflavin-deficient rats, and fungi, was used to ascertain whether a flavin plays a role as a sensitizing pigment for photomorphogenesis in the fungus Trichoderma . Roseoflavin inhibited blue light induced conidiation of a riboflavin-requiring auxotroph of Trichoderma . Colonies pre-incubated with roseoflavin needed six times more light to saturate conidiation. Roseoflavin did not change the dark rate of conidial development indicating that it interfered only with the photoact. A revertant from the riboflavin auxotroph strain was not inhibited by roseoflavin. Simultaneous addition of 10 μ M riboflavin prevented inhibition by 6.4 μ M roseoflavin. Thus, roseoflavin inhibition is probably specific, possibly replacing riboflavin or one of its metabolites in the light reactions. There was no detectable shift in the action spectrum towards the green where roseoflavin absorbs; thus it did not replace a flavin as an efficient photoreceptor. 相似文献
139.
Kaupp M Reviakine R Malkina OL Arbuznikov A Schimmelpfennig B Malkin VG 《Journal of computational chemistry》2002,23(8):794-803
We report the first implementation of the calculation of electronic g-tensors by density functional methods with hybrid functionals. Spin-orbit coupling is treated by the atomic meanfield approximation. g-Tensors for a set of small main group radicals and for a series of ten 3d and two 4d transition metal complexes have been compared using the local density approximation (VWN functional), the generalized gradient approximation (BP86 functional), as well as B3-type (B3PW91) and BH-type (BHPW91) hybrid functionals. For main group radicals, the effect of exact-exchange mixing is small. In contrast, significant differences between the various functionals arise for transition metal complexes. As has been shown previously, local and in particular gradient-corrected functionals tend to underestimate the "paramagnetic" contributions to the g-tensors in these cases and thereby recover only about 40-50% of the range of experimental g-tensor components. This is improved to ca. 60% by the B3PW91 functional, which also gives slightly reduced standard deviations. The range increases to almost 100% using the half-and-half functional BHPW91. However, the quality of the correlation with experimental data worsens due to a significant overestimate of some intermediate g-tensor values. The worse performance of the BHPW91 functional in these cases is accompanied by spin contamination. Although none of the functionals tested thus appears to be ideal for the treatment of electronic g-tensors in transition metal complexes, the B3PW91 hybrid functional exhibited the overall most satisfactory performance. Apart from the validation of hybrid functionals, some aspects in the treatment of spin-orbit contributions to the g-tensor are discussed. 相似文献
140.